SDMS HTTP Error 500 on Windows Server 2016 — IIS handler mappings fix

Applies to: SDMS on Windows Server 2016 — fresh install or upgrade to version 1.8.6 or earlier

After installing or upgrading SDMS on Windows Server 2016, the SDMS site may fail to load with an HTTP 500 error. This article explains the cause and the steps to fix it.

Symptom

Opening the SDMS site in a browser displays:

HTTP Error 500.0 – Internal Server Error

Root cause

On Windows Server 2016, the SDMS installer creates handler mappings for .NET v2 only. Mappings for .NET v4 are not added, which causes the site to fail when it attempts to load .NET v4 components.

IIS Manager — Handler Mappings for the SDMS site showing only .NET 2.0 handlers after a fresh install. The .NET 4.x handlers that SDMS requires are absent, which is the direct cause of the HTTP 500 error.

Resolution

If upgrading from SDMS 1.6.136 or 1.7.8x to 1.8.6+

Before fixing the handler mappings, change the SDMS application pool to use .NET 4 and 64-bit mode:

1. Open IIS Manager (inetmgr.exe).
2. Go to Application Pools and select the SDMS application pool.
3. Click Basic Settings in the Actions pane.
4. Set .NET CLR Version to .NET CLR Version v4.0.30319.
5. Click OK.

IIS Manager — Basic Settings dialog for the SDMS application pool. The ".NET CLR Version" dropdown is set to ".NET CLR Version v4.0.30319". This must be changed from v2 to v4 before the site will load correctly.

6. Still on the application pool, click Advanced Settings.
7. Set Enable 32-Bit Applications to False.

8. Click OK.

   

IIS Manager — Advanced Settings dialog for the SDMS application pool. "Enable 32-Bit Applications" is set to False, switching the pool to 64-bit mode. This is required for SDMS 1.8.6+ on Windows Server 2016.

Fix the handler mappings (required for all affected scenarios)

After completing any application pool changes above, revert the SDMS site's handler mappings to inherit the correct parent configuration:

1. Run inetmgr.exe.
2. In the left panel, expand Sites > Default Web Sites.

3. Click the SDMS website node.

   

4. Double-click Handler Mappings under the IIS group.
5. In the Actions pane on the right, click Revert to Parent.

IIS Manager — Handler Mappings page for the SDMS site. The Actions pane on the right shows the "Revert to Parent" link. Clicking this replaces the incomplete .NET v2-only mappings with the full parent configuration that includes .NET v4 handlers.

6. Click Yes on the confirmation dialog.

The SDMS site will now load correctly.

Version-specific summary